The Great Wall of China

The Great Wall of China represents one of the biggest construction projects in history. It seems entirely plausible that the whole thing can be easily seen from space — it is the world’s longest wall, after all.

Or so you would think. It turns out that the wall isn’t visible from space, a point that was clarified in 2003 by Yang Liwei, one of China’s own astronauts and a man who would definitely know where to look. The Chinese government has now vowed to remove that myth from every student textbook in the country.

Former NASA astronaut Jeffrey Hoffman says that although he couldn’t see the Great Wall of China from space, he could make out runways, desert roads, and irrigation ditches, simply because they contrasted with their surroundings.